Precisely striking the bacterially infected site and avoiding damage to healthy tissues is vital for bacterial infection therapy. Herein, an intelligent antibacterial platform that triggers the aggregation of gold nanoparticles (AuNPs) on bacterial surface based on the acidic environment of bacterial infection was developed. Also, the AuNPs functionalized with an acidity-triggered moiety (Pep-DA) exhibited a charge-convertible properties to target bacterial infection sites. The positively charged acidity-triggered AuNPs endowed the AuNPs aggregate on negatively charged bacterial surface in the infected site rather than in healthy tissues, achieving the threshold to interparticle plasmonic coupling effect among AuNPs, and killing bacteria accurately under NIR irradiation light. This acidity-triggered aggregation strategy provides an excellent therapeutic mode for treating focal bacterial infections with no critical damage to healthy tissues.